Heretofore, it has been believed that effecting a reaction with compounds containing oxygen such as first stage oxygenated compounds including alcohols, second stage oxygenated products such as aldehydes or ketones, or third stage oxygenated compounds such as acids would require the presence of stoichiometric amounts of metal halides such as aluminum chloride. However, as will hereinafter be shown in greater detail, it has now been discovered that esters may be reacted with carboxylic acids in the presence of a catalytic amount, that is, less than a stoichiometric quantity based on the carboxylic acid, of a tin halide whereby the acid may be esterified. By being able to utilize only catalytic amounts of the tin halide, it is possible to prepare the desired compounds at a relatively low cost, and thus render the process more attractive from an economic standpoint.
This invention relates to a process for the esterification of carboxylic acids. More specifically, the invention is concerned with a process for the esterification of carboxylic acids whereby said acids are reacted with an ester in the presence of a tin halide.
As hereinbefore set forth, it has now been discovered that carboxylic acids may be esterified by treating the acid with an ester and a tin halide thereby effecting a transesterification reaction which results in the formation of an ester of the carboxylic acid. This transesterification reaction is important inasmuch as the reaction offers a means of obtaining esters which otherwise would have to be prepared in a difficult manner. Esters will find a wide variety of uses in the chemical field. For example, sec-butyl acetate is used as a solvent for nitrocellulose, lacquers, thinners, nail enamels, celluloid products, etc.; sec-heptyl formate is used in artificial fruit essances; sec-octyl acetate is used in perfumery and flavors; allyl caproate is also used in perfumery and flavors; vinyl acetate is used in polyvinyl acetate resins, in latex paints, adhesives, textile finishing, etc.; benzyl acetate is used as an essential ingredient of artificial jasmine and other flowery perfumes, as a solvent for cellulose acetate and nitrate, in oils, lacquers, polishes, etc.; benzyl formate is used as a solvent as well as in perfumery and flavors; benzyl succinate is used in organic syntheses, etc.
It is therefore an object of this invention to provide a transesterification process.
A further object of this invention is to provide a process for the esterification of carboxylic acids by treating the acids with an ester in the presence of a tin halide.
In one aspect an embodiment of this invention resides in a process for the transesterification of a carboxylic acid which comprises reacting said acid with an ester in the presence of a tin halide catalyst at reaction conditions, and recovering the resultant esterified carboxylic acid.
A specific embodiment of this invention is found in a process for the transesterification of a carboxylic acid which comprises reacting propionic acid with allyl acetate in the presence of anhydrous stannic chloride at a temperature in the range of from about 0.degree. to about 150.degree. C. and a pressure in the range of from about atmospheric to about 100 atmospheres and recovering the resultant allyl propionate.
Other objects and embodiments will be found in the following further detailed description of the present invention.